1. Field of the Invention
The present invention relates to an apparatus and a method for vector descriptor representation and multimedia data retrieval, and more particularly to, an apparatus and a method for vector descriptor representation and multimedia data retrieval, which can hieratically represent and store vector descriptor of multimedia data and retrieve multimedia data using the stored representation information.
2. Description of the Related Art
Recently, it has brought out the problem to retrieve and store multimedia data because of bulky multimedia data. Moreover, a demand not for text-based retrieval but for content-based retrieval is being increased to retrieve the bulky multimedia data fast and as a user wants. To solve the problems, attempts to represent descriptors of multimedia information and correlation between the descriptors of multimedia information have been continued.
For example, multimedia data consists of image and sound, and image consists of various objects: each of them having features of color, shape and texture; and a group of images having a motion feature. If the images are stored only in themselves, there is difficulty to retrieve.
To solve the above problem, a method for effectively representing each object or representation unit has been proposed. Especially, in case that several descriptors are represented in the form of vector, stable retrieval result cannot be obtained if the retrieval is performed in the state that several elements of vector are omitted, because vectors have different meanings respectively.
Moreover, if vector descriptors are all stored to tremendous multimedia data in construction of database, large storing space may be wasted according to circumstances. Furthermore, several users may want to maintain only small descriptor metafile.
However, as described above, because several feature values cannot be omitted from the vector descriptors, there is a problem that data cannot be represented as a flexible amount.
FIG. 1 shows a block diagram of a conventional vector descriptor representing apparatus.
As shown in FIG. 1, the conventional vector descriptor representing apparatus includes a quantization unit 400 for quantizing a great deal of feature values described by vector descriptor and a variable-length coding unit 401 for coding each feature value quantized in the quantization unit 400 in variable length and storing the coded feature values in a feature value storing unit 402.
FIG. 2 shows a block diagram of a multimedia data retrieval device using the conventional vector descriptor representing apparatus.
As shown in FIG. 2, the multimedia data retrieval device using the conventional vector descriptor representing apparatus includes a variable-length inversely coding unit 502 for inversely coding the coded feature values in variable length, an inverse quantization unit 503 for inversely quantizing the feature values inversely coded in the variable-length inversely coding unit 502 and restoring the inversely coded feature values to original feature value, and a comparing unit 505 for comparing the original feature value restored by the inverse quantization unit 503 with multimedia data stored in a multimedia database 504 and retrieving multimedia data according to the compared result.
The operation of the conventional vector descriptor representing apparatus and multimedia data retrieval device using it will be described in more detail as follows.
First, the vector descriptor (X) in the conventional vector descriptor representing apparatus shown in FIG. 1 can be formularized as follows:                                                         〈              MARGIN              〉                        ⁢                                                  ⁢                          〈              TR              〉                        ⁢                                                  ⁢                          〈              P              〉                        ⁢            X                    =                                    [                                                                                          X                      1                                                                                                                                                          〈                        IP                        〉                                            ⁢                                              〈                        P                        〉                                            ⁢                                              X                        2                                                                                                                                                                                〈                        IP                        〉                                            ⁢                                                                        〈                          P                          〉                                                ·                                                                                                                                                                                〈                        IP                        〉                                            ⁢                                              〈                        P                        〉                                            ⁢                                              X                        N                                                                                                        ]                        ⁢                          〈              IP              〉                                      ,                            Formula 1            
wherein X is the vector descriptor consisting of first to Nth feature values (X1, . . . and XN).
To represent the vector descriptor (X), the quantization unit 400 quantizes the first to Nth feature values (X1, . . . and XN) constituting the vector descriptor (X) and provides to the variable-length coding unit 401. The variable-length coding unit 401 codes the first to Nth feature values (X1, . . . and XN) quantized by the quantization unit 400 in variable length and stores the coded feature values in the storing unit 402.
Next, the operation of the multimedia data retrieval device using the conventional vector descriptor representing apparatus shown in FIG. 2 will be described in more detail as follows.
The variable-length inversely coding unit 502 inversely codes the coded feature values in variable length and provides to the inverse quantization unit 503.
The inverse quantization unit 503 inversely quantizes the feature values provided from the variable-length inversely coding unit 502 and provides to the comparing unit 505.
The comparing unit 505 compares the feature values provided from the inverse quantization unit 503 with multimedia data stored in the multimedia database 504 and outputs retrieval data according to the compared result.
As previously described, the conventional multimedia data retrieval device retrieves multimedia data using the feature values of the vector descriptor represented by the vector descriptor representing device.
However, as previously described, in the conventional vector descriptor representing device, when data is represented, because it is difficult to determine importance of the first to Nth feature values (X1, . . . and XN) of the vector descriptor (X), there is a problem that cannot represent multimedia data by a small amount of data.
Furthermore, also in the multimedia data retrieval device using the conventional vector descriptor representing apparatus, because it is difficult to determine importance of the first to Nth feature values (X1, . . . and XN) of the vector descriptor (X), there is a problem that cannot represent multimedia data by a small amount of data.